叠加导频在EM迭代信道估计算法中的应用

Application of Added pilot in EM Channel Estimation Algorithm

为了提高正交频分复用系统的传输效率,提出了一种基于叠加导频的最大期望迭代信道估计算法。该算法不需要信道和接收数据的统计特性,信道估计在一帧内完成,没有因发送导频而带来的带宽损失,并可以通过选择迭代次数实现系统性能和计算复杂度之间的折衷。仿真结果表明,在不牺牲系统带宽效率,损失较少发射功率条件下,该算法能很快收敛到给定参数的信道,很好地跟踪信道的时变特性,取得较好的系统误码性能。

To improve the transmission rate of Orthogonal Frequency Division Multiplex(OFDM)systems, an Expectation Maximization(EM)iterative semi-blind channel estimation algorithm based on the added pilot symbols is proposed.The algorithm does not require the channel statistics and does not have band loss because of pilot symbols transmitted.The tradeoff between system performance and algorithm complexity is realized by choosing the iteration number.At the expense of a little transmitted power,the simulation results show that the proposed algorithm converges to the known channel parameters and the performance is improved significantly compared with the interpolation methods for Pilot Symbols Assistant Modulation(PSAM)OFDM systems.